In recent years, with respect to electronic equipments such as mobile equipments and information equipments, there is a rapid demand for reduced size and enhanced performance of these equipments. With this tendency, it has also been required to reduce a size of parts used in these equipments such as inductance devices and impart a high performance thereto. In particular, inductance devices used in power supply circuits have been required to minimize the deterioration in inductance and the increase in core loss as DC superimposition characteristic observed when flowing AC and DC therethrough in a superimposed manner. In addition, the inductance devices for power supply circuits undergo generation of heat and therefore temperature rise when used under the condition in which a large amount of AC is flowed therethrough. Therefore, it has been required that the inductance devices have a less change in temperature dependence of magnetic permeability even when exposed to the temperature rise.
To meet these requirements, there have been proposed Ni—Zn—Cu-based ferrites to which various additives are added. There are known Ni—Zn—Cu-based ferrite to which silicon oxide is added (Patent Document 1), Ni—Zn—Cu-based ferrite to which bismuth oxide, tin oxide and chromium oxide are added (Patent Document 2) and the like.